1. Field of the Invention
The present invention relates to magnetic resonance (MR) apparatus and methods for reconstructing images from signals received by a moveable RF coil assembly, the current three-dimensional (3D) position and 3D orientation of which guides the location of the nuclear magnetization excited during the imaging process, and also relates to a RF coil assembly for receiving and transmitting capable of being moved across a patient while guiding the location of the MR imaging.
2. Description of the Related Art
Conventional magnetic resonance (MR) is based on batch acquisition and retrospective image reconstruction and patient diagnosis. In such conventional MR imaging, during a preparation phase, the patient along with necessary RF receiving coils are arranged in an examination zone. During actual MR measurement, which typically requires a comparatively long time, usually a large volume, either multiple 2-D slices or one 3-D image, within the sensitivity range of the receiving coil is measured. Patient diagnosis can be made only after collection of a complete set of MR data and its reconstruction into a diagnostic image. If the region of interest in the patient turns out to be situated outside the planned examination zone or of the sensitivity range of the receiving coil, the patient and the receiving coil have to be repositioned, and the entire measurement repeated.
In contrast, a different and interactive way of imaging is known from ultrasound imaging. There, the position and orientation of the ultrasound probe necessarily determines the imaging plane, and ultrasound images are displayed in rapid succession, even in real time, as they are received by the probe. Accordingly, the ultrasound imaging plane can be interactively determined by manipulation of the ultrasound probe in order to obtain at once images of greatest clinical usefulness.
In recent years several developments have occurred which have begun to alleviate some problems previously associated with MR imaging. First, an almost real-time capability has been developed, because the speed with which MR images can be acquired has been significantly reduced by means of improved magnetic gradient field systems and of new imaging procedures. Second, new main-field magnet designs have been developed which allow for significantly improved patient access in comparison to prior tunnel-shaped MR systems. Finally, noteworthy developments in other fields, such as the field of image-guided surgery, include position detection systems capable of accurate guidance of instruments during critical surgical procedures, and position detection systems capable of accurate positioning of catheters in a patient.
What remains lacking, however, in the current state of the MR arts is apparatus and methods which provide for interactive MR examination having the known flexibility of ultrasound methods.
Citation of a reference herein, or throughout this specification, is not to be construed as an admission that such reference is prior art to the Applicant's invention of the invention subsequently claimed.